Mars Tectonics & Volcanology

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MARS TECTONICS &
VOLCANOLOGY
Zachary Gallegos
University of New Mexico / Mars One
Mars Orbiter Laser Altimeter Map
Plate Tectonics
• Lithospheric plates sliding
on the asthenosphere,
above the mantle
• Exists on Earth
• Theory proposed in the
early 1900’s
• Does it exist on other
bodies in the solar
system?
Plate Tectonics
• Recycles material
• Regulates the atmosphere
• CO2 sequestration and output
• Linked with mantle
convection
• Push new material to surface
at divergent boundaries
• Pulls old material into the
Earth at convergent
boundaries
Tectonics of Earth
• Picture of plates
Plate boundaries
• Divergent
• Spreading apart
• Convergent
• Moving together
• Strike-slip
• Sliding past
Divergent
• Mid-Atlantic ridge
• Oceanic
• East African Rift
• Continental
• Rio Grand Rift
• Continental
Convergent
• Mariana Islands/Trench
• oceanic-oceanic
• Pacific Northwest
• oceanic-continental
• Himalayas
• continental-continental
Strike-slip
• San Andres fault
• right lateral
Plate Tectonics of Mars
Tectonics of Mars
• Mars seems to lack global, Earth-like tectonics
• Too small?
• Not enough water?
• Large scale faulting
• HUGE scale rifting
Topography
• Mars’ planetary dichotomy
• Not tectonic in origin
• Bolide impact , water resurfacing
• Slow sloping at the dichotomy
• not pronounced
• Earth’s dynamic lithosphere
• Tectonic in origin
• Steeply sloping at the margins
• Continental and oceanic crust
Magnetics
• Mars lacks a current magnetic field
• Magnetic reversals recorded on Earth
Magnetics
• Possible magnetic reversals recorded in early Martian crust
Interior of Mars
• Smaller/colder
• Less water
Faulting
• Tectonic movement
• Normal (extension)
• Reverse (compression)
• Strike-slip (lateral)
Faulting on Mars
• Thrust faulting
• Amenthes Rupes
• Normal faulting
• Circum-Tharsis
• Strike-slip faulting??
• Within Valles Marineris
Faulting on Mars
• Circum-Tharsis
• Extensional faulting
Valles Marineris
• Giant tectonic fissure in
the crust
• Not the result of plates
• Result of Tharsis uplift
• Length: > 4,000km
• Width: > 200km
• Depth: > 7km
• Largest known valley in
the solar system
Valles Marineris
• Nearly ¼ or the planets circumference
• Nine times longer than the grand canyon
Vallis Marineris
Volcanology
• Study of volcanoes
• Volcanoes bring new material to the surface from below
• Lava, ash, gas
Volcanology of Earth
• Most of Earth’s volcanism is related to plate tectonics
• Divergent and convergent boundaries
Volcanology of Mars
• No planetary tectonics
• Shield forming
• Hot spot volcanism (e.g. Hawaii)
• Mostly basaltic in compositions
• From ultramafic komattiatic to dacitic
Rocks and Minerals
• Mars has a different volcanic signature than Earth
Why Basalt?
• Hot spot volcanism produces basalt
Volcanism and Tectonics
• With no tectonics, volcanoes grow to enormous size
Montes
• Mons are large shield volcanoes
• Earth analogue: Hawaii
• Gentle slopes < 6°
Ascraeus Mons
Pavonis Mons
Arsia Mons
Tholi
• Tholus is a term for
smaller, dome shaped
volcanoes
• Older than Mons
• Buried by later flows
• Steeper flanks
• Different material than
Montes?
• Less material than
Montes?
Patera
• Term given to small volcanoes with large calderas
• Latin translation: shallow drinking bowl
• Larger calderas than the tholi
• Probably represent larger volcanoes
• Buried beneath flows and sediment
Rootless Volcanoes & Pseudocraters
• Show no sign of magma conduit
• Analogues on Earth erupt due to a magma body flowing
over a surface or subterranean water source
Martian Volcanic Provinces
Tharsis
• Largest volcanic province on Mars
• 25% of the planets surface
• Avg. 7-10km above datum
• Youngest flows on Mars
Tharsis
Arsia Mons
Olympus Mons
• Largest mountain in the solar system
• Height: > 22km
• Diameter: > 500km
• Slope: ~ 4°
• 6 nested calderas
• 3.5km deep
Alba Mons
• North of Tharsis buldge
• Very low slopes ~ .5°
• 1600km across
• Rises 3km above plains
Elysium
• Second largest volcanic
province
• 1,700x2,400 km
• Elysium Mons
• 13km high
• Hecates Tholus
• North
• Albor Tholus
• South
Syrtis Major
• 1200km across
• 2km high
• 2 calderas
• Nili Patera, Meroe Patera
• Silica rich rocks
• Dacite & Granite
Isidis
Basin
Highland Patera
• Near the Hellas impact basin
• Impact induced volcanism along fractures?
Arabia Terra
• Low relief Patera
• Structures that look like
Earth’s supervolcanoes
• e.g. Eden Patera
Questions?
Geography of Mars
Volcanic Provinces
Exploration Sites
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